Radiometric analyzers prior to this invention have featured photometers and reflectometers of various kinds, often used with an incubator, for detecting a radiometric change in a test element. Examples of analyzers are described in commonly owned U.S. Application Ser. No. 177,050, filed on Aug. 11, 1980, by Jessop, entitled "Analyzer Apparatus Featuring a Simplified Incubator," wherein means are provided for automatically moving the test element into and out of the reflectometer station.
One useful reflectometer is a fiber optics reflectometer having an optical scanning head comprising a light-emitting optical fiber and a light-collecting optical fiber. Such a scanning head gives optimal performance if it is pressed against the test element during scanning, to minimize light losses. However, if such a fiber optics reflectometer were to be used in an analyzer of the type described in the above-noted Jessop application, there would be constant wear on the optical scanning head when the test element is pushed off the head by the automatic feed mechanism, after being scanned. Such constant wear could be avoided by gearing and linkages which are activated to move the reflectometer out of contact with the element prior to movement of the test element out of the reflectometer station. However, such gearing mechanisms are too cumbersome and expensive. A simpler mechanism is needed to permit the use of a contacting reflectometer, such as the fiber optics reflectometer described above.